The present invention relates to hair conditioning compositions with sufficient rigidity to sustain their own shape. The usual form of such compositions is a stick or bar.
Most individuals buy and use a hair shampoo for its cleansing properties. In addition to having clean hair, a consumer also desires sufficiently-conditioned hair that, for example, is easy to comb when wet, feels smooth and does not fly away. However, hair shampoos are generally formulated with highly effective anionic surfactants that primarily clean as opposed to condition the hair. Anionic surfactants not only remove the dirt and soil from the hair, but also remove sebum naturally present on the surface of the hair fibres. Shampoos also do not disentangle wet hair and do not impart residual conditioning benefits to dry hair, such as manageability or stylability.
Therefore, the desirable cleansing properties of shampoo compositions imparted by the anionic surfactants, nonionic surfactants or amphoteric surfactants, or mixtures thereof, have the disadvantage that they tend to leave the hair in a cosmetically-unsatisfactory condition. This has resulted in the use of separate conditioning compositions, typically applied separately from the shampoo, to improve these undesirable physical characteristics. Typically, after washing the hair with shampoo and rinsing, a conditioner composition is applied to the hair for a period of time and then rinsed off. Problems such as wet combing are solved by treating the shampooed hair with a conditioner composition that coats the hair shaft and causes the individual hair shafts to resist tangling and matting because of the conditioner residue retained on the shaft.
Typically, conditioning compositions are in the form of liquids or cream-like emulsions or lotions which are applied to the hair, left for a period of time on the hair and then rinsed out. A problem associated with such liquid compositions is that the more liquid the compositions, the harder it is to hold them in the hands and the harder it is to measure them out, i.e. compositions tends to escape through the fingers. Moreover, the more liquid these compositions, the more liable they are to escape from their packaging, for example during transport and when the consumer is going on holiday.
As a result, conditioner compositions have been formulated in solid form, i.e. a form in which they are capable of maintaining a predetermined shape without the aid of any external structure. Such solid conditioner forms have the advantages of requiring a lesser amount of packaging because they are more concentrated and also of being smaller more handy products to transport.
Solid sticks are used as the delivery form for many types of cosmetic products such as deodorants, lip conditioners, and colour cosmetics. Stick formulas are generally based on either silicones, glycols and soap, or waxes. The glycol/soap base, which is water soluble or dispersible, is the traditional form for deodorants and antiperspirants. It consists primarily of water, glycols (such as glycerin or propylene glycol), alcohol and/or glycol esters, and is made into a solid form by addition of soap, usually sodium stearate.
WO97/12584 (Estee Lauder) describes a solid silicone composition comprising a 3-20 wt % polyethylene solidifying agent having an average molecular weight of less than 1000, and 20-97 wt % of a non-volatile silicone fluid. The compositions additionally comprise other pharmaceutically or cosmetically acceptable materials which are soluble in or compatible with the silicone fluid, e.g. colourants, oils, fragrances, sunscreens. The compositions can be applied to the hair or skin.
U.S. Pat. No. 4,344,446 (Bjurman and Babcock) describes a hair care package comprising a scalp cleanser in solid form and a cleaning and conditioning shampoo typically in the form of a liquid gel. The solid scalp cleanser contains a soap, an amphoteric surfactant, an antimicrobial agent and a waxy emulsifier, such as polyoxyethylene fatty alcohol ethers or high molecular weight fatty acid mono- or di-esters of polyethylene glycol, to provide rigidity to the composition.
Solid compositions based on waxy materials tend to have an undesirable greasiness to them. In addition, it is also difficult to incorporate hydrophilic active agents to such compositions and it can be difficult to rinse then out of the hair.
Consequently, other structuring agents have been looked at. EP 823,252 (A-Veda Corporation) describes cosmetic hair conditioning compositions in solid form containing a film-forming polymer and a cosmetically acceptable vehicle. The gel forming agent used to provide structure to the solid forms is a soap. However, the compositions also preferably include a nonionic surfactant, a polyhydric aliphatic alcohol, a sugar and a lower alcohol.
Attempts have increasingly been made to obtain solid compositions comprising higher concentrations of an aqueous phase. Typically such compositions are gels made from a combination of hydrophilic gelling agent and water. These have the disadvantage that they tend to be brittle and easily broken in use.
One way of addressing this problem has been to include particulate filler/structuring material in the compositions to add rigidity.
U.S. Pat. No. 5,824,296 (L""Oreal) describes a solid hair composition, which may be a conditioner, containing a particulate structuring agent. The particles are preferably of low density and hollow particles and are capable of being washed out of the hair by rinsing. Suitable particles are made from glass or thermoplastic materials such as nylon, polymers or copolymers of acrylonitrile, vinylidene chloride etc. Example 11 is a conditioner comprising 0.8 wt % behenyltrimonium chloride, 4 wt % of a cationic silicone emulsion, 8 wt % EXPANCEL particles, and over 85 wt % water. The EXPANCEL particles are hollow deformable particles of an expanded copolymer of vinylidene chloride/acrylonitrile/methacrylate.
WO 00/78280 (L""Oreal) describes solid cosmetic compositions which contain an continuous aqueous phase comprising a hydrophilic gelling agent and a lamellar filler. The compositions have a hardness which provides both easy disintegration and good stick adhesion. The compositions are primarily directed at use on the skin, either directly or via a sponge and reportedly provide freshness on application and a homogeneous coating.
There are several problems associated with the use of particulate materials in hair conditioner formulations including possible negative effects on the conditioning performance and the added expense of having to include an ingredient not normally present in a conventional hair conditioner formulation.
In conclusion, the solid hair conditioner formulations of the prior art require the use of additional components not generally present in conventional hair conditioner compositions in order to provide structure/rigidity to the compositions. This leads to disadvantages as discussed above.
Surprisingly, we have now found that hair conditioner compositions in solid form can be prepared without the need for additional structuring aids by simply lowering the water content of a conventional conditioner formulation.
The hair conditioning solid the present invention improves upon the prior art by providing a composition which is cheap, i.e. it does not require any specialised structuring agents, is easily rinsed from the hair and has a hardness which allows it to be readily applied to the hair whilst maintaining its shape. In addition, because essentially the same formulation is used as in a conventional liquid conditioner apart from the level of water, it is possible to manufacture solid and liquid forms of product on the same site which gives a considerable saving in production cost.
Accordingly, this invention provides a hair conditioner composition in solid form comprising
(i) at least 5 wt % cationic surfactant, and
(ii) at least 5 wt % fatty alcohol material
wherein the composition contains less than 80 wt % water.
Additionally, this invention provides for use of hair conditioner compositions in solid form as described above for conditioning the hair.